Bridge .analyticsScreen View modifier

Fixes #49

Author: dfabulich

Package.swift

@@ -93,6 +93,7 @@ let package = Package(
         .target(name: "SkipFirebaseAnalytics", dependencies: [
             "SkipFirebaseCore",
             .product(name: "FirebaseAnalytics", package: "firebase-ios-sdk", condition: .when(platforms: [.macOS, .iOS, .tvOS, .watchOS, .macCatalyst])),
+            .product(name: "SkipUI", package: "skip-ui"),
         ], resources: [.process("Resources")], plugins: skipstone),
         .testTarget(name: "SkipFirebaseAnalyticsTests", dependencies: [
             "SkipFirebaseAnalytics",

Sources/SkipFirebaseAnalytics/SkipFirebaseAnalytics-SwiftUI.swift

@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: LGPL-3.0-only WITH LGPL-3.0-linking-exception
+#if !SKIP_BRIDGE
+#if SKIP
+import SwiftUI
+
+struct LoggedAnalyticsModifier: ViewModifier {
+    /// The name of the view to log in the `AnalyticsParameterScreenName` parameter.
+    let screenName: String
+    
+    /// The name of the view to log in the `AnalyticsParameterScreenClass` parameter.
+    let screenClass: String
+    
+    /// Extra parameters to log with the screen view event.
+    let extraParameters: [String: Any]
+    
+    func body(content: Content) -> some View {
+        // Take the content and add an onAppear action to know when the view has appeared on screen.
+        content.onAppear {
+            // Log the event appearing, adding the appropriate keys and values needed for screen
+            // view events.
+            var parameters = extraParameters
+            parameters[AnalyticsParameterScreenName] = screenName
+            parameters[AnalyticsParameterScreenClass] = screenClass
+            Analytics.logEvent(AnalyticsEventScreenView, parameters: parameters)
+        }
+    }
+}
+
+public extension View {
+    /// Logs `screen_view` events in Google Analytics for Firebase when this view appears on screen.
+    /// - Parameters:
+    ///   - name: Current screen name logged with the `screen_view` event.
+    ///   - class: Current screen class or struct logged with the `screen_view` event.
+    ///   - extraParameters: Any additional parameters to be logged. These extra parameters must
+    ///       follow the same rules as described in the `Analytics.logEvent(_:parameters:)` docs.
+    /// - Returns: A view with a custom `ViewModifier` used to log `screen_view` events when this
+    ///    view appears on screen.
+    func analyticsScreen(name: String,
+                         class: String = "View",
+                         extraParameters: [String: Any] = [:]) -> some View {
+        // `self` is the view, we're just adding an `LoggedAnalyticsModifier` modifier on it.
+        modifier(LoggedAnalyticsModifier(screenName: name,
+                                         screenClass: `class`,
+                                         extraParameters: extraParameters))
+    }
+}
+
+#endif
+#endif